GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The engine control module (ECM)/powertrain control module (PCM) supplies a ground path for the CRNK relay when start enable has been requested. The ECM/PCM monitors this circuit for conditions that are incorrect for the commanded state. If the ECM/PCM detects an improper circuit condition, DTC P0615 will set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0615 Starter Relay Control Circuit

Conditions for Running the DTC

System voltage is between 9-16 volts.

Conditions for Setting the DTC

    • The ECM/PCM detects an improper voltage level on the control circuit that controls the CRNK relay.
    • The condition exists for at least 2 seconds.

Action Taken When the DTC Sets

    • The ECM/PCM will not illuminate the malfunction indicator lamp (MIL).
    • The ECM/PCM will store the conditions present when the DTC set as Fail Records data only.

Conditions for Clearing the MIL/DTC

The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

Diagnostic Aids

Ignition system DTCs set with the ignition switch in the START position if the CRNK relay or the starter is inoperative. When the ECM/PCM enables starter operation, the ECM/PCM also initiates the diagnostic test routines for DTCs P0335, P0340, and P0385. If a condition exists which prevents the engine from cranking, the ECM/PCM will not receive signal input from the CKP and CMP sensors, and the DTCs will set.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may assist in diagnosing the condition. The information may help determine how often the condition that set the DTC occurs.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Listen for an audible click when the CRNK relay operates. Turn the ignition switch back and forth from the ON to START positions. Repeat this as necessary.

  2. Tests for voltage at the coil side of the CRNK relay.

  3. Verifies that the ECM/PCM is providing ground to the CRNK relay.

  4. Tests if ground is constantly being applied to the CRNK relay.

Step

Action

Yes

No

Schematic Reference: Starting and Charging Schematics

Connector End View Reference: Engine Electrical Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Turn the ignition back and forth from the ON to START positions.

Does the CRNK relay click with each command?

Go to Step 3

Go to Starter Solenoid Does Not Click

3

  1. Turn OFF the ignition.
  2. Remove the CRNK relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the battery positive voltage of the CRNK relay coil circuit with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 8

4

  1. Connect a test lamp between the control circuit of the CRNK relay and the battery positive voltage of the CRNK relay coil circuit.
  2. Turn the ignition back and forth from the ON to START positions.

Does the test lamp turn ON and OFF with each command?

Go to Step 6

Go to Step 5

5

Test the control circuit of the CRNK relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 7

6

Inspect for poor connections at the CRNK relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 9

7

Inspect for poor connections at the ECM/PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 10

8

Repair the battery positive voltage circuit of the CRNK relay. Refer to Connector Repairs .

Did you complete the repair?

Go to Step 11

--

9

Replace the CRNK relay.

Did you complete the replacement.

Go to Step 11

--

10

Replace the ECM/ PCM. Refer to Control Module References for replacement, setup, and programming.

Is the action complete?

Go to Step 11

--

11

  1. Review and record scan tool Fail Records data.
  2. Clear DTCs.
  3. Operate vehicle within Fail Records conditions as noted.
  4. Using a scan tool, monitor the Specific DTC Information for DTC P0615.

Does the scan tool indicate DTC P0615 failed this ignition?

Go to Step 2

System OK